ELECTRO-PHYSIOLOGY, 339 



the function of the electric organ. The temperature of the water in which the 

 fish is pLiced has great influence on that function. If the torpedo he placed in 

 water at four or five degrees ahove zero, or still colder, it ceases at once to move 

 or to give discharges. It is not, therefore, dead, and may be kept for a long 

 time at this low temperature in a limited quantity of sea-water, since, respiring 

 less, the air therein will for a longer time supply its requirements. After im- 

 mersion for a few minutes in water at -{•15° to 20°, the torpedo resumes the 

 electric function which had been suspended while it was in the cold water. 

 Placed in water of -f30° or 40^, the fish gives several discharges, and soon 

 dies ; the circulation and respiration, quickened by the higher temperature, 

 probably increase the nervous action, but respiration presently ceases, because 

 the air of the water is too rapidly consumed. By measuring and analyzing the 

 air disengaged in the water in which torpedoes have been kept, I have found 

 that the exercise of the electric function is attended with greater activity of 

 respiration, whence, under equal conditions, there is considerably less oxygen 

 in the air disengaged in water in which there has been a torpedo provoked to 

 give many discharges, than in that in which a torpedo has been left in repose. 

 It should be added that the coagulation of the albumina of the substance of the 

 organ destroys the electric function. 



The ultimate conclusion to which all the experiments made upon the torpedo 

 and other electric fishes conduct its is the following : 



" The irritation of the nerve of the electric organ transmitted in the direction 

 of its ramification, when arrived at the extremity of the nerve, and consequently 

 in the elementary cellule of the m-gan, electrically polarizes that cellule, and by 

 an action analogous to electro- magnetism develops transversely to its direc- 

 tion, and upon the two faces of each diaphragm, opposite electrical states." 



There can be no difficulty in understanding, in the light of this principle, the 

 chief properties of the electric organ. Each prism of the organ resulting from 

 a great number of superposed cellules, it is clear that the poles of the organ 

 must alv/ays be at the extremities of the prisms, and that the electric tension 

 will increase with the height of the prisms, and with the energy of the nervous 

 action. It is not so easy to understand, at least by the law of the voltaic bat- 

 tery, the influence of the volume of the cellules, and especially of the number of 

 the prisms. These two conditions should cause a variation of the internal re- 

 sistance of the batteries and of the prisms, and not of the electro-motive force, 

 and hence not of the intensity of the discharge, since this is generally trans- 

 mitted by bodies which have a much greater resistance than the organ of the 

 torpedo. That the tension d^nonds on the number of cellules is proved by the 

 influence of the height of the piisms ; and is proved also by the discharge of the 

 torpedo, which, at an equal height of organ, is stronger than that of the gym- 

 notus, because the elementary cellules in the former are much the most delicate. 



If we Avere acquainted with the intimate nature of the electro-motor element 

 of these fishes, we should very probably know how the number of the prisms 

 and their division act in the discharge. It is a fact that the discharge in the 

 galvanometer increases with the extension of the electrodes which touch the 

 organ of the torpedo. Since each of the prisms is polarized independently one 

 of the other under the irritation of its proper nerve, it may be inferred that the 

 total discharge is the effect of the sura of the simultaneous, though independent, 

 discharges of the different prisms. 



It remains, then, to know what is the intimate manner of action of the ele- 

 mentary electro-motor, and thence to discover the relation between the distribu- 

 tion of the nerves in the organ, its structure, and the distribution of the electri- 

 cal states in the organ itself. It is only of late that we have succeeded in throw- 

 ing some light on these problems, and I shall terminate the study of the electric 

 function of these animals by briefly stating the principal results obtained on this 

 subject. 



